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Crevice Corrosion in a Subsea System — Aspect Before Analysis

84 images

TryOil and GasML00060corrosionBoilerML00071brittle fractureAductile behaviorASTMfatigueFerrous AlloyshydrogenLow Alloy Steelfractureembrittlementstress corrosion
Condition: Fabrication Defect Microstructure: Ferritic Bainitic clear all
M

Material

79 classified

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P

Product

96 classified

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Ap

Application

37 classified

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C

Condition

84 classified

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Cm

Capture method

52 classified

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Df

Detail focus

208 classified

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Standard22
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The Materials
Image Database

84 images
Macrography of the longitudinally seam weld of the 24" diameter tube, showing that it was welded from both sides and there is a segregation line in the center of the tube thickness.
737
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - NItal Etched MacroDf - Seam
Micrographic detail of the forging lap defect that appears at the nut surface like a crack, filled with oxides. The nut presented a martensitic structure in the center of the nut, but in the regions adjacent to the defect the structure is ferritic-bainitic due to decarburization. There are several globular oxides (grey spots) that became entrapped during the forging.
654
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Nital Etched Micrography by OMDf - Crack
The macrography of a longitudinal section of the pipe and connector, at the welded joint, shows that the welding was conducted from both side of the groove, starting from the ID and finishing from the OD, ID later machined flush. The cracking was detected by ultrasonic test and the macro shows that it is at the fusion line, growthing into the weld metal. See the schematic drawing in the next figure
535
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - NItal Etched MacroDf - Longitudinal Section
Image of the magnetic particle test, using a white contrast, presenting the cracks at the surface of the weld metal. The cracks are transverse to the weld and do not propagate into the base metals. A forged T in the right side of the figure and a thick wall tube in the left side of the figure, both in P12 CrMo steel.
1044
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Aspect by NDTDf - Cracks
The internal surface of the 2 1/2" thickness plate drum was welded to attach a baffle plate (1/4" thick) using two fillets (one in each side of the plate to shell), but the welding procedure was not suitable since cracks appeared underbead, although they were detected only after 6 month in operation, when the baffle was removed. The picture shows a macrography of the surface, with the cracking.
698
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - NItal Etched MacroDf - Cracking
Mooring chain aspect, after several years of operation. Transverse cracking, revealed by dye check, close to the flash butt weld.
441
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Aspect by NDTDf - Crack

More from these cases

ML00177 — Cr-Mo Seam Welded TubeM - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Identification of the regions of metallographies of the base metal, heat affected zone (HAZ) and weld metal. Locations in the root, in the center of the thickness and close to the tube OD (external surface).
118
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - NItal Etched MacroDf - Welded Joint
BASE METAL SURFACE - Ferritic structure, grain refined.
90
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Base Metal
BASE METAL SURFACE - The micrography (transverse to the tube) presents the ferritic/pearlitic/bainitic structure.
75
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Granular structure
BASE METAL SURFACE - The microstructure of the base metal is ferritic/pearlitic/bainitic.
74
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Grain refined structure
HAZ SURFACE
72
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - Nital Etched Micrography by OMDf - Last Bead HAZ

+20 more from this case →

ML00099 — Forging Defect in a Cadmium Plated NutM - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Micrography of the nut in a section transverse to the surface indication. There are several microcracks (parallel and perpendicular to the nut surface) filled with oxides. The nut presented a martensitic microstructure in the center of the thickness and a ferritic-bainitic microstructure at surface and adjacent to the defect, due to decarburization occurred during high temperature forging.
130
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Nital Etched Micrography by OMDf - Crack
The general aspect of the 1 1/8" 2H nut, presenting rejectable indications that appear like cracks, located in the face and in the lateral side of the nut.
46
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Aspect Before AnalysisDf - General View
Aspect in detail of the 1 1/8" 2H nut face, presenting rejectable indications that appear like cracks.
49
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Aspect Before AnalysisDf - Lap
The general aspect of the lateral side of the 1 1/8" 2H nut, presenting a rejectable indication that looks like a straight crack.
48
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - Aspect Before AnalysisDf - Lap
Micrographic detail of the lap at the nut surface, as polished. The 20 microns cadmium layer is evident, penetrating in the lap.
46
VIEW
ML00099 / Jan.2018
Forging Defect in a Cadmium Plated Nut
M - Medium Carbon SteelP - NutAp - PipingCd - Fabrication Defect
Cm - As polished micrographyDf - Lap

+2 more from this case →

ML00072 — Liquation Cracks in a High Strength JointM - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Schematic drawing presenting the longitudinal section of the pipe and connector at the welded joint
105
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Identification drawingDf - Longitudinal Section
Hot cracking at the fusion line of the connector side, in a welded joint between a forging and a pipe, in a macrographic sample. The region of the heat affected zone of the connector presents a dendritic aspect suggesting that the forging reduction rate of the connector was not too high and did not broke the cast structure.
110
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - NItal Etched MacroDf - Welded Joint
The connector was welded to the pipe from both (internal and external) sides, a PWHT was applied and the part was machined. The UT indication was detected during final inspection.
78
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Aspect Before AnalysisDf - General View
Micrography of the welded joint fusion line presenting the liquation cracking. The weld metal is in the right side (bottom) and the forged connector heat affected zone is in the left side (top).
83
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracking
The liquation crack is a hot crack in the base metal (at the HAZ) that induces a solidification crack in the weld metal.
66
VIEW
ML00072 / Jan.2018
Liquation Cracks in a High Strength Joint
M - Low Alloy Medium Carbon QTP - Longitudinal Seam Welded PipeAp - O&G Well DrillingCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Weld Metal

+11 more from this case →

ML00071 — Reheating Cracking of a CrMo Vessel WeldM - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Aspect of the butt welded joint surface, after grinding to remove the reinforcement, polishing and macro etching. There are multiple cracks, transverse to the weld and restricted to the weld metal. The surface hardness are 167HB for the tube (left side), 180 HB for the Forged T (right side) and 272 HB for the weld metal, suggesting lack of a suitable PWHT.
181
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Surface AspectDf - Cracks
The morphology of the cracking in the weld metal is intergranular (in the previous austenite grain boundaries), and branched. The replication technique was adopted to define the nature of the cracks.
148
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital etched, OMDf - Cracks
Detail of the weld metal intergranular and branched cracking (in the previous austenite grain boundaries). The replication technique was adopted to define the nature of the cracks.
125
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital etched, OMDf - Cracks
The forged T presented a ferritic perlitic/bainitic structure at the surface, where the replica was conducted. The base material material hardness is 180 HB.
121
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital etched, OMDf - Ferrite and Bainite
The thick wall tube presented a bainitic structure at the surface, where the replica was conducted. The base material material hardness is 167 HB.
108
VIEW
ML00071 / Jan.2019
Reheating Cracking of a CrMo Vessel Weld
M - CrMo SteelP - In Field WeldAp - EnergyCd - Welding Defect
Cm - Nital etched, OMDf - Bainite

+10 more from this case →

ML00008 — Cold Cracks in CMn Steel Pressure VesselM - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Micrography of a longitudinal section of the shell plate base metal, presenting a typical ferritic-perlitic microstructure.
149
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Higher magnification of the ferritic-perlitic microstructure of the shell plate in the longitudinal section.
129
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Ferrite and Pearlite
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ.
123
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ. The cracks are mainly located at the fusion line.
118
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks
Cold cracking of the fillet weld adopted to attach a flat support into a vessel shell in the internal side, using an unsuitable welding procedure that created a too high hardness HAZ. Several internal cracks at the fusion line.
101
VIEW
ML00008 / Nov.2017
Cold Cracks in CMn Steel Pressure Vessel
M - CMn SteelP - In Field WeldAp - BoilerCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Cracks

+2 more from this case →

ML00013 — Welding Cracks in Mooring ChainM - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Micrography of a longitudinal section of the mooring chain in the base metal. The low magnification reveals the banded structure of the rolled bar. The base metal microstructure is bainitic..
79
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Banded Structure
Micrographic detail of the bainitic microstructure of the base metal in the longitudinal section.
72
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Bainite
Micrography of a longitudinal section of the mooring chain at the flash welded region. The banded structure is deformed by the upset, close to the weld metal that is ferritic-bainitic.
61
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite
Micrographic detail of the ferritic-bainitic weld metal, autogenous flash butt weld.
56
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Nital Etched Micrography by OMDf - Bainitic Ferrite
Welded region etched to reveal impurities. The banded structure creates a continuous network parallel to the weld metal.
50
VIEW
ML00013 / Apr.2017
Welding Cracks in Mooring Chain
M - Low Alloy Low Carbon QTP - Welded PartAp - OffshoreCd - Welding Defect
Cm - Micro by OM, picric acid+FeCl3+H2O etchDf - Segregated Regions

+3 more from this case →

View all 84 images in the Atlas →

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The location of the threaded fitting started leaking after less than five years in service. Although the corrosion rate was not high, the localized material loss in the threaded surface of the carbon steel flange allowed the connection leakage.
769
VIEW
ML00184 / Apr.2023
Dissimilar Steels in a Threaded Connection
M - Low Carbon SteelP - ForgingAp - OffshoreCd - Localized Dissolution
Cm - Aspect Before AnalysisDf - General View
Front wheel 17 x 7J of a passenger vehicle (identified as WHEEL 1) that broke during a car accident on a road.
1644
VIEW
ML00183 / Dec.2022
Ductile Behavior of an Aluminum Wheel
M - Aluminum Silicon MagnesiumP - CastingAp - AutomotiveCd - Ductile Behavior
Cm - Aspect Before AnalysisDf - General View
Tool fixture 5" long, nominal diameter 2", presenting a recess 1/2" deep from two sides. The rupture occurred about 2" from the end of the rod. Scale in milimeters.
523
VIEW
ML00182 / Jul.2022
Brittle Fracture of a LAS Fixing Rod
M - Low Alloy Medium Carbon QTP - StemAp - Mechanical IndustryCd - Brittle Fracture
Cm - Aspect Before AnalysisDf - General View
Pinion of hypoid gearbox, assembled in a 1560-mm long shaft that operated during more than 60,000 hours, and removed from service due to unacceptable wear damage.
1028
VIEW
ML00181 / Apr.2022
Wear of a Carburized Hypoid Gear
M - Low Alloy for Thermochemical TreatmentP - Pinion-crown assemblyAp - ShipCd - Wear
Cm - Aspect Before AnalysisDf - General View
Aspect of the 3 1/2" diameter tube after the water leakage in high temperature.
962
VIEW
ML00180 / Mar.2022
Local Melting of Copper Cooling Tubes
M - Pure CopperP - Cooling TubeAp - SiderurgyCd - Overheating
Cm - Aspect Before AnalysisDf - General View
2" drain line from the main 10" line. The leakage occurred at the margin of the weld, a short time after the introduction of the reinforced ribs to reduce vibration.
641
VIEW
ML00179 / Feb.2022
Hydrides in Titanium Weld
M - Unalloyed TitaniumP - In Field WeldAp - Chemical IndustryCd - Hydride Formation
Cm - Field photoDf - General View
The drilling connector, 21" diameter, presented a crack at the margin of the weld in the forging side (left side of the weld in the figure).
745
VIEW
ML00178 / Jan.2022
Cold cracks in Cr-Mo Welded Forging
M - CrMo SteelP - ForgingAp - O&G Well DrillingCd - Welding Defect
Cm - Aspect Before AnalysisDf - General View
Macrography of the longitudinally seam weld of the 24" diameter tube, showing that it was welded from both sides and there is a segregation line in the center of the tube thickness.
737
VIEW
ML00177 / Dec.2021
Cr-Mo Seam Welded Tube
M - CrMo SteelP - Longitudinally Seam WeldedAp - Fired HeaterCd - Not according to spec
Cm - NItal Etched MacroDf - Seam
The titanium rotor blade of a flowmeter broke after two years in service in an acid environment, containing H2S.
339
VIEW
ML00176 / Nov.2021
Hydride Formation in a Titanium Blade
M - Unalloyed TitaniumP - BladeAp - Oil and GasCd - Hydride Formation
Cm - Aspect Before AnalysisDf - General View
Aspect of the wire rope, 1 1/2" diameter, presenting regions of flattened areas at the surface of the outer wires. It is a 6 x 19 Seale construction, right regular lay.
552
VIEW
ML00175 / Aug.2021
Localized External Wear of a Wire Rope
M - High Carbon SteelP - Wire RopeAp - Oil and GasCd - Wear
Cm - Aspect Before AnalysisDf - General View
The carcass was manufactured using niobium stabilized plates, grade AISI 347, with circumferential welds, where the through wall cracks were detected.
300
VIEW
ML00174 / Jul.2021
Carburization of a 347 SS Welded Joint
M - Austenitic Stainless SteelP - Fabrication WeldAp - EnergyCd - Carburization
Cm - Field photoDf - General View
Aged microstructure of the HP stainless steel, modified with 1%Nb, cast fitting, tubular, operating for 6 years in a furnace which design temperature is 1100°C. The material presented a network of primary carbides, white and grey, and an austenitic matrix with coalescing secondary precipitation. Some voids. The Vickers identation indicates a hardness value about 260HV 100g in the aged austenitic matrix.
492
VIEW
ML00173 / May.2021
Welding Cracks in an Aged HP Cast Fitting
M - Heat Resistant SteelP - Cast FtittingAp - PetrochemicalCd - Welding
Cm - Kalling Etched Micrography by OMDf - Microhardness identations

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